If the earth were to stop spinning around the sun, half the Earth would be in daylight for half the year while the other side would be in darkness. The second half of the year it would be reversed. Temperature variations would be far more extreme then they are now. The side of the earth that had the sun would be much warmer – the side without the sun would be much colder. The temperature difference would affect the wind circulation too. The air would move from the equator to the north and south poles rather then in wind systems parallel to the equator as they are now.
Another thing would happen is the sun's position in the sky.
The sun would just have a seasonal motion up and down the sky towards the south due to the orbit of the Earth and its axial tilt. You would see the elevation of the Sun increase or decrease in the sky just as we now see the elevation of the Sun change from a single point on the Earth due to the Earth's daily rotation.
As an example, say we live at 30 degrees North latitude. In the Summer, at a longitude where the Sun was exactly overhead, it would slide gradually to the horizon as Fall approached, but since the Sun has moved 90 degrees in its orbit, it would now be due west. As Winter approached, you would now be located on the dark side of the Earth. You would have to move to a longitude 180 degrees around the Earth to see the Sun 1/2 way up the sky because in the Winter, the Sun is 50 degrees south of its summer location in the sky.
There would be other effects of the Earth's rotation slowing also. The magnetic field of the Earth is generated by a dynamo effect that involves its rotation. If the Earth stopped rotating, the magnetic field would no longer be regenerated and it would decay away to some low, residual value due to the very small component which is 'fossilized' in its iron-rich rocks. There would be no more 'northern lights' and the Van Allen radiation belts would probably vanish, as would our protection from cosmic rays and other high-energy particles. Losing this protection would cause serious health issues.
The interesting thing is, Global Warming will likely, over time, cause the earth’s rotation to slow down or even stop altogether. But that will happen over hundreds of thousands of years.
· 1 decade ago